The importance of industrial and marine cleaners which clean metal parts effectively is clearly recognized. Although such cleaners are available in the marketplace, there is a need for improved cleaners which can be easily handled and used. Typically the cleaners used for such applications are either solutions or macroemulsion cleaners. However, there are disadvantages in using such products.
One of the major disadvantages of these macroemulsion cleaners is that they are not convenient to use since they must be prepared as a water emulsion just prior to use due to the instability of the macroemulsion. Water emulsions are cumbersome to use and a significant source of cleaning failures, especially under shipboard conditions, because they break into two phases. Furthermore, mixing can result in inconsistent results due to variations in the concentration of components of the macroemulsion as prepared.
Another major disadvantage of such cleaners is that they are milky emulsions which leave milky residues on cleaned equipment and require a further water rinse which is undesirable.
Additionally, solution cleaners based upon solvents, and even many macroemulsion cleaners often have low flash points which can be unsafe when the cleaners are used for cleaning hot equipment, particularly air coolers on diesel engine trains. The air cooler of a diesel train is conventionally cleaned using such a freshly prepared macroemulsion in water. The water is added to eliminate the flash point, which would otherwise create a potential hazard on the hot equipment.
Even so, due to the vagaries in macroemulsion preparation on shipboard just prior to use, a potentially hazardous flashpoint may occur. Usually these macroemulsion cleaners are stable for only a few hours. Consequently, if the personnel involved in the cleaning are suddenly needed elsewhere during the course of the air cooler cleaning treatment or do not carry out the macroemulsification properly, the emulsion and water could separate with the result that the emulsion would again have a low flashpoint. This could result in a hazard and also in reduced cleaning effectiveness.
In addition to these major disadvantages, there are several other deficiencies macroemulsion cleaners have when used to clean industrial and marine equipment:
(a) The cleaners do not drain effectively which results in excessive post rinsing. PA1 (b) The cleaners generate foam during the cleaning process. PA1 (c) Cleaning effectiveness is sometimes inadequate. PA1 (d) These cleaners are available only as a concentrate. The use of such concentrates requires on-site mixing. PA1 (a) an organic solvent; PA1 (b) an anionic/nonionic surfactant blend; PA1 (c) a glycol ether; PA1 (d) morpholine; and PA1 (e) water. PA1 (a) from about 10 to 12 weight percent of an organic solvent such as aromatic or aliphatic hydrocarbon solvent, dichlorotoluene, terpene hydrocarbon, or oxyalcohol esters, or M-pyrol; PA1 (b) from about 12 to 18 weight percent of a surfactant blend comprising anionic and nonionic surfactants wherein the weight ratio of anionic surfactant to nonionic surfactant is from 1:4 to 4:1 with the nonionic surfactant being at least 8 to 10 weight percent of the microemulsion cleaner; PA1 (c) from about 18 to 22 weight percent of DPM; PA1 (d) from 5 to 10 weight percent of morpholine; PA1 (e) from 0.001 to 0.1 weight percent of a defoamer; and PA1 (f) from 35 weight percent water for the concentrate and up to 60 percent by weight of water for the ready-to-use microemulsion cleaner.
The other major class of cleaners consist of detergents in solutions of water or solvents which also have limitations. Water-based formulations are ineffective on oil and soils. Solvent-based detergents possess flash points which render them hazardous when applied to thermally or electrically "live" equipment.